Wet electrostatic precipitators (WESP) have been used for many years to remove dust, acid mist and other particulates from water-saturated air and other gases by electrostatic means. In a WESP, particulates and/or mist laden water-saturated air flows in a region of the precipitator between discharge and collecting electrodes, where the particulates and/or mist is electrically charged by corona emitted from the high voltage discharge electrodes. As the water-saturated gas flows further within the WESP, the charged particulates matter and/or mist is electrostatically attracted to grounded collecting plates or electrodes where it is collected. The accumulated materials are continuously washed off by both an irrigating film of water and periodic flushing.
This type of system is used to remove pollutants from gas streams exhausting from various industrial sources, such as incinerators, coke ovens, glass furnaces, non-ferrous metallurgical plants, coal-fired generation plants, forest product facilities, food drying plants and petrochemical plants.
The electrodes used in WESPs are commonly formed of stainless steel. In International Patent Application Publication No. WO 2008/154,735 and International Patent Application No. PCT/CA2010/000377 assigned to the assignee hereof and the disclosures of which are incorporated herein by reference, we have described the provision of WESP parts constructed of electrically-conductive corrosion and spark-resistant carbon composites. Such materials show comparable or superior properties to stainless steel and permit WESPs to be constructed at lower cost.